1. Field of the Invention
The present invention relates to V-blade snowplows, and more particularly to replaceable cutting edges of such plows.
2. Description of the Related Art
The most common type of snowplow has a straight blade which mounted to and extends across the full width of the front of a vehicle, such as a truck. In the simplest form, the angle of the blade with respect to the front of the vehicle is fixed at an angle so that snow being pushed by the blow is forced to one side. A more versatile straight plow enables blade to pivot with respect to the front of the vehicle so that the snow can be pushed to either side or straight ahead.
Another type of snowplow utilizes a V-blade which has two angled sections that meet at a forward edge and push the snow to both sides of the vehicle. This type of plow can incorporate a mechanism to alter the angle of the blades with respect to the each other. Typically, each blade is hinged to a center section of the plow frame and separate double-acting hydraulic cylinder and piston arrangements pivot the blade about the vertical hinge. This enables the two sections of the blade to be positioned in a standard “V” configuration that pushes the snow to each side, in a concave or scoop arrangement, or in a straight line that can be angled to either side of the vehicle.
In use, the bottom, or cutting, edge, of the blade scrapes against the surface being plowed. Usually that surface is very hard, often asphalt or concrete, which wears away the cutting edge. As a consequence the typical blade has a sacrificial cutting edge in the form of a metal plate that is removably mounted along the bottom edge. The edge plate, rather than the main section of the blade, is subjected to the wear during use. When most of the cutting edge plate has worn away it is replaced with a new one. It is more economical to replace the sacrificial cutting edge plate than the entire blade.
A characteristic of a V-blade is that the two blades are spaced apart under the center frame section which creates a gap through which some of the material being plowed can pass. This could leave in a rib of snow down the center of the area being plowed. To prevent this from occurring, prior blades spanned the gap with a flat rubber belt that was bolted to the cutting edges of each blade extending in front of the hinge on the center section. This belt flexed and stretched as the angle of the two blades changed. U.S. Pat. No. 6,108,946 describes an alternative solution that employs a semi-conical, solid catcher block beneath the center section of the V-blades. The catcher block closed the gap between the blade and its conical shape allowed the two sections to pivot without opening a gap. However the semi-conical catcher wore at a different rate than the cutting edges and had to be replaced at a different time. Furthermore, the solid block of material did not yield when struck by an object, such as a stone or other type of protrusion from the surface being plowed.
The outer tips of the blade also are subject to wear when plowing against a curb. In addition, significant force may be exerted on the edge of the blade upon striking a curb, which can adversely affect the blade hinge and the cylinder-piston arrangement used to pivot the blades. These forces, if significant, also can damage other components of the snowplow.